Lightning-arrester.



PATENTE'D AUG. 11, 1908'. E. HEDDAEUS & R. NOTHNAGBL. LIGHTNING ARRESTER.

APPLIOATION FILED NOV. 30, 1907.

Lren'rnrne annns rnn.

Specification of Letters Patent.

Patented Aug. 1 1, 1908.

Application filed November 30, 1907. Serial'fio. 404,542.

To 'zll'u/homitmay concern:

Be it known that we, ERNsT \TTEDDAEUS and RUDOLF NOTHNAGEL, subjects of the.

German Emperor, and residents of Bilbao, a bpain, have invented certam'new and. useful lmprovements in Lightning Arresters, of

whichthe following is a specification.

Our invention relates to improvements in lightning arresters of that class in which a spark gap is formed between two bodies the discharging surfaces of which are movable relatively to each other, so that the arc moves from one point of the gap to another one, whereby it will more readily be destroyed.

The improvements are particularly designed for use in such devices that are used for protecting electrical circuits and instruments from the destructive effect of lightning and other abnormally high tension currents. Devices of this class heretofore in use are not as effective as is required for a reliable operation of electrical lants, but they give rise to violent disturbances and considerable variations of the tension of the apparatus, whenever an atmospheric discharge occurs.

Now, the object of our improvements is to provide an apparatus of this class, in which all the advantages of devices heretofore in use are combined. And for this purpose, the discharging surfaces are so constructed as to increase their distance when moving relatively to each other, whereby the are formed across the gap is safely destroyed Devices of this class heretofore in use and particularly designed for protecting a circuit from lightning have been found unsatisfactory for protecting a circuit from abnormally high tension currents, because, for this latter purpose, they were not sufliciently sensitive, and they could not be made more sensitive without considerably reducing the length of the sparking gap. On the other hand, devices designed for protecting the circuit from high tension currents would not be reliable when used as lightning arresters, because the resistance of the grounding conductor is too high, which resistance, however, could not be sufficiently reduced, because otherwise the dischargers were liable to be injured or destroyed by an arc of an excessive strength. No w, an important advantage of our improved protecting device consists in the fact that it will be equally effective in rotecting the circuit from lightning and rom high tension currents.

An important feature of the invention consists in having both discharging surfaces movable, which movement takes place so as to raise the arc, whereby the latter is destroyed within a comparatively short time,

and the high tension current is gradually conducted to the earth. This feature of our invention is based on the fact, that the arc, by its thermal action, is caused to move upwards, which upward movement is assisted by the said mechanical means of raising the discharging part of the gap. Vv'e thereby succeed in gradually and safely destroying the arc.

For the purpose of explaining the invention, we have shown an example embodying the same in the accompanying drawing, in which the same letters of reference have been used in all the views to indicate corresponding parts.

In said drawing-Figure 1, is a vertical cross-section of the apparatus taken on the line AA of Fig. 2, andFig. 2, is a plan of the same.

In the example shown in the drawing, the apparatus comprises a pair of wheels a and I) mounted in suitable insulated bearings of a frame 0. The wheel a connected to the high tension conductor has a circular shape. The wheel I) which is grounded is of a cam like outline, four cam surfaces being shown in the example illustrated. The radial extension of each of the cam surfaces gradually decreases from a certain maximum to a mini mum. The wheels a and b are rotated by suitable means, a spring actuated motor being suitable for small apparatus, while an electric motor will be used for larger sizes. For this urpose, the wheels are connected to suitab e pulleys g mounted on the same axes therewith. By the said motor the wheels are rotated in the direction of the arrows shown in Fig. 1. It will readily be understood, that, by so rotating the wheels, the are produced between the same will be raised upwards, whereby the thermal action of the same is assisted. it will therefore readily be destroyed. Furthermore, it will pa ati-vely narrow at the beginning will rally become broader so as to incrase to J maximum required for a sati actory 0, .tion. Th are produced between the d'schargers will therefore be safely broken by iicreasin the distance of the discharging cos, one. it Will be produced again either b be next cam surface of the same Wheel, or

by the next cam surface of another wheel discharging surfaces of the same, the discharging surfaces of the other pair of Wheels haveso far approached each other, that an arc can be formed across the-same. If in this case the smallest distance of the dis- .1 difference of the radii of the discharging cam. surfaces 1, millimeters, the smallest spark gap will be QH-y/Z millimeters.

Where three pairs of Wheels are connected in shunt, the cam surfaces of which are displaced at angles of 30, the spark gap can tot he more than ac+ 11/3 millimeters.

In case of multiphase currents we prefer to rigidly connect the Wheels of the different conductors.

the arrangement described apparatus of desired degree of sensitiveness can be no lo, in which, notwithstanding, the arc is safely destroyed.

The speed of. the discharging surfaces said bodies rotate.

rging surfaces be 9: millimeters, and thescares varies between 0.25 and 0.75 meters per second.

We claim:

1. An apparatus of the diameter described, comprising two, rotating discharge bodies connected respectively to the circuit scribed, con'iprising a pair of oppositely ro' tating discharge bodies mounted on parallel axes, one of said bodies having a peripheral cam whereby the space separating said bodies will be grai'lua ly varied in Width as 4. An a imaratus of the character described, com )rising a plurality of pairs of discharge Wheels respectively connected to the circuit to be protected and to the earth, means to rotate one wheel of each of said pairs, and cam surfaces formed on said rotatable Wheels, the positions of said cam surfaces relatively to the cooperating Wheels 

